Electron Paramagnetic Resonance ofV3+Ions in Zinc Oxide

The paramagnetic resonance of trace amounts of ${\mathrm{V}}^{3+}$ in single-crystal hexagonal zinc oxide is reported. The EPR spectrum is fitted with an axially symmetric spin Hamiltonian with five empirically determined parameters: $D$, $g_{\mathrm{II}}$, $g_{\perp }$, $A$, and $B$. The spin-Hamiltonian parameters are interpreted in terms of the Racâh parameter $B$, the crystal-field parameters $\mathrm{Dq}$, $\mathrm{Ds}$, $\mathrm{Dt}$, and the spin-orbit coupling constant $\lambda$. The values of these parameters derived from the EPR data are consistent with a model in which the ${\mathrm{V}}^{3+}$ replaces a ${\mathrm{Zn}}^{2+}$ in a trigonally elongated tetrahedral site. This is in agreement with a recent redetermination of the crystallographic unit-cell parameters of ZnO.